Circuit breaker



May 2, 1939- J. G. JACKSON E-r AL. 2,156,760Y

CIRCUIT BREAKER Filed OCt. 31, 1935 3 Sheets-Sheet l E, [6 Q -Qp/ 6E o I lu P55 ('53 '56) um Hl am IH [ma: @MJ

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ATTORNEY.

J. G; JACKSON ET AL 2,156,760

CIRCUIT BREAKER Filed oct. 31, 1935 s sheetsheet 2 May 2, 1939.

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CIRCUIT ,BREAKER Filed Oct. 5 1, 1935 Y 3 SheetS-Sheef 3 E- E-"F- y :f| 27 ,5 E y l a za f6 b 26 I 5 24 D f2 y 52 f2 E ifi@ f) um d l2 5 n, f' 2 f U i l :"y 72a I -9 -Q- 2 26 4l f z5 25 gli l [/f" I 7 Y 9 2 r l E r [l im: [j i 7 JP 2v Jah, a Jffgl r9 dlldce THX/e2?,

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Patented May 2, 1939 UNITED STATES PATENT OFFICE CIRCUIT BREAKER John G. Jackson and Wallace T. Allen, Detroit, Mich., assignors to Square D Company, Detroit, Mich., a corporation of Michigan Application October 31, 1935, Serial No. 47,524

Claims.

Another object of this invention is to provide f 10 an electric circuit breaker having a plurality of individual mechanisms with a common bus supporting the stationary contact of each of the mechanisms.

Another object of this invention is to provide an improved and economical form of circuit breaker having a plurality of individual mechanisms and common mounting features.

Other objects and features of this invention Will be readily apparent to those skilled in the art from the following specication and the appended drawings illustrating certain preferred embodiments of the invention in which:

Figure 1 is a top plan View of the circuit breaker apparatus according to the present invention with the outer cover broken away. Y

Figure 2 is a partial sectional view Itaken on the line II-II of Figure 1.

Figure 3 is a sectional View taken on the line III- III of Figure l.

Figure 4 is a sectional viewtaken on the 'line IV-IV of Figure 3.

Figure 5 is a detail sectional view taken on the line V--V of Figure 3.

Figure 6 is a view similar to Figure 2 showing the parts in automatic tripvposition.

Figure 7 is a view similar to Figure 2- showing the parts in manual trip position.

Figure 8 is a View similar to Figure 2 showing the parts in resetting position.

o Figure 9 is a partial sectional view showing a slightly modied form of construction.

Figure 10 is a partial sectional view showing a further modication.

The circuit breaker apparatus as illustrated 5 comprises an oute'r sheet metal enclosing box I having an openable cover 2 hingedly or otherwise mounted thereon. Within this outer box is mounted one or more sealable circuit breaker units. In the specific embodiment illustrated there are shownl two circuit breaker units sealably Iand supportably mounted upon a single plate which mounts them within the enclosing box. It is readily understood that any number of these units may bemounted upon a single i sealing and supporting plate or that each unit may have an individual sealing and supporting plate permitting separate manipulation of each separate unit. The outer box may be equipped with the usual knockouts, cover latch and similar features as is conventional in the art.

Each circuit breaker embodies a base 3 having a plurality of individual compartments 4. In each of these compartments is disposed an individual circuit breaker mechanism. Extending across the base in common with the individ- 10 ual compartments and mechanisms is a bus 5 secured to the base by means of the sealing rivet 6.

The dividing walls between the compartments are cut away to receive the bus 5 and a spacer l5 'l serves to rigidly mount the bus against the Wall. The bus is provided with an enlarged opening receiving an insulating spacer 8 serving to insulate the rivet 6. At the back of the base is disposed an insulating fibre plate 9 which is 20 in turn backed up by the supporting and mounting plate I I. The rivet 6 extends through to the back of the plate II and hence mounts the parts together in scalable relationship.

The r,opening in the dividing walls between 25` the compartments is preferably enlarged to permit the gases generated by the rupture of an. arc between any pair of contacts to be discharged within the entire circuit breaker interior and thus render less necessary any vent to 30l the outer air. These walls dividing the interiors into compartments are not at all essential and may be entirely omitted if desired.

The stationary contact I2' of each mechanism is conductingly and resiliently supported upon 35 the bus 5 by means of a resilient arm I3. A Woven conducting strip I4 may be used to interconnect the contact and bus to lower the resistance. Also supported on the bus is the base of a .U-shaped latch I5. 'Ihe ends of the strips 4o I3 and I4 and the base I5 of the latch may be Welded, riveted, or otherwise rigidly secured to the bus 5. Y

These elements at their points of connection are provided with an opening receiving the interior ends of a push button I6 inslidable and rotatable relation. The portion of the push button within this opening is provided with a peripheral groove I'I cooperating with a tongue I8 on the bus to limit the rotary movement of 50 the push button. A compression springIQ dis-- posed intermediate the bus 5 and the push button- I 6 is stressedto bias the push button outwardly and to rotate it in a counterclockwlse direction to engage the tongue .I8 withone side 55 v 25 rigidly mounted thereon.

. 21 extends through an opening in the member -ISIS of the peripheral groove I1. A pin 20 is provided at the lower end of the push button to limit its outward movement.

The push button is provided with a latching groove 2| adapted to be engaged by the ends 22 of the latch I5 to holdthe push button inwardly against the bias of spring I9. Slidably mounted upon push button I6 is an insulating member 23 having a bimetallic strip 24 and movable contact The free end of the bimetal carries a conductor lug 26 and a latch pin 21. The latch pin 21 is loosely maintained in position at the end of the bimetal by holding strip 28 rigidly mounted thereon. The latch pin 23 and is received in a peripheral groove 29 in the push button I6. 'Ihe pin 21 thus serves to latch the member 23 to the push button and provide for a common movement thereof as a unit.

An inclined notch 3I leads to the groove 29 at one point on the periphery of the push button and enables pin 21 to slide therein to release the latching engagement. A compression spring 32 biases member 23 away from the bus 5. The member 23 is provided with surfaces 30 adapted to engage and separate the latch arms 22 when the member 23 moves upwardly under the bias of the spring 32.

A conducting strip 33 is disposed on a shelf on the outside of each chamber and has a conductor lug 34 on one end thereof. A flexible lead 35 interconnects the conductor lugs 26 and 34. The conductor 33 is rigidly mounted on the base by riveting connection with a metallic insert 40 mounted in the base. This insert is interiorly threaded to receive the terminal stud 36.

The operation of an individual circuit breaker mechanism will now be described. The parts as shown in Figure 2 and at the bottom in Figure 3 are in their normal on position. Upon the occurrence of an overload the bimetallic strip 24 will Warp clockwise pulling the pin 21 out of the groove 29 and permitting the member 23 to move upwardly under the bias of the compression spring 32, thus carrying the movable contact 25 away from the stationary contact I2 in its upward movement. The surfaces 30 on the member 23 engage the arms of the U-shaped latch I5, movingthem apart, thus unlatching the push button I6 and permitting it to move upwardly under the bias of its spring I9. The upward movement of the push button is limited by the pin 29 of the lower end thereof.

With the member 23 and the -push button I6 both in their upward positions, the latch pin 21 will be again received within the groove 29 -as soon as the bimetallic strip 2l is cool. 'I'he positions of the parts in the automatic trip position is shown in Figure 6 and at the top in Figure 3. To reset the circuit breaker, the push button is pressed inwardly as shown in Figure 8 until the latch arms 22 engage the latching groove 2I on the push button, whereupon the contacts will be4 member 23 is again free to move upwardly, separating, as it moves, the latch arms 22. The

latching engagement. The limits of rotation of the push button are determined by the engagement of the tongue I8 with the groove I1.

With the breaker as herein illustrated, it is seen that the stationary contacts are electrically connected together by means of the bus 5. In feed-.

ing through this breaker, one of the mechanisms will constitute a main circuit breaker through which the current will be led in to the bus 5. 'I'he remaining circuit breaker mechanisms will constitute branch circuit breakers leading to separate circuits. This places a main and load breaker in series with any short circuit which may occur. In some instances it may be desirable to extend the bus 5 to the exterior of the breaker and this construction has been illustrated in Figure 9 wherein the end of the bus 5 projects beyond the breaker and is provided with a terminal washer 31 and stud 38. The opening in the outer wall may be sealed by a tab 39 on the bre plate 9. In this embodiment the terminal on the bus 5 may serve either as a bus tap or as a main terminal for the breaker. When used as a main terminal all individual mechanisms will then function as individual branch circuit breakers leading to separate circuits. When used as a bus tap one of the individual mechanisms will still function as a main circuit breaker leading to the bus 5 and the feeding through the individual mechanisms will be as in the preferred embodiment. How'ever, feeding from the bus tap 38 will only be through the main breaker to the bus 5.

In the modification `shown in Figure 10 the stationary contact I2 is directly and rigidly supported on the bus 5 and the movable contact 25 is supported as a resilient spring arm 4I mounted on the member 23. In this modification the spring arm 4I serves the same function as the spring strip I3 in maintaining an adequate pressure between the cooperating contacts.

While the latch I5, the operating springs and the push button have all been shown as mounted upon and cooperating with the bus 5, it is obvious thatthese parts maybe carried by any supporting surface and that they have been here shown as cooperating with the bus for the purposes of simplicity, particularly in the embodiment illustrated.

In the appended claims the terms box and cover are to be construed to include cabinet and door respectively.

While certain preferred embodiments of the invention have been specificallyv disclosed, it is understood that the invention is notl limited thereto as many variations will be readily apparent to those skilled in the art .and the invention is to be given its broadest possible interpretation within the terms of the following claims:

What is claimed is:

1. Electric circuit breaker apparatus comprising a plurality of aligned, spaced circuit breaker mechanisms including relatively movable contacts and means for automatically separating said contacts in response to overload, a common, elongated bus bar for said mechanisms having one contact of each mechanism conductively supported thereon in positions spaced along its length, and a sealable enclosure for said mechanisms and bus bar preventing access thereto.

2. An electric circuit breaker comprising a `unitary base having a plurality of aligned, spaced compartments therein, a circuit breaker mecha- -nism mounted in each compartment and comprising relatively movable contacts and manual unitary base having a plurality of aligned, spaced compartments therein, a circuit breaker mechanism mounted in each of said compartments and comprising relatively movable contacts and manual and automatic means for separating said contacts, an elongated bus bar connected to said base and extending across said aligned compartp tments, one contact of each mechanism being conductively supported by said bus, and a cover attachable to said base to form a scalable enclosure for lsaid mechanisms and bus bar.

4. An electric circuit breaker comprising a plurality of individual mechanisms including stationary and movable contacts and means for automatically separating said contacts in response to overload, a common bus for said mechanisms, each stationary contact being resiliently and conductively mounted on said bus in the path of its cooperative movable contact.

5. Electric circuit breaker apparatus, comprising a common conductor having a plurality of contact faces supported thereon,V a unitary base mounted over said conductor, said base having a plurality of compartments therein with one of said contact faces in each of said compartments, an'individual automatic electric circuit breaker mechanism in each of said compartments and including a movable contact adapted to cooperate with said contact face to perform the switching operation, and means for sealably closing said compartments. v

6. Electric circuit breaker apparatus comprising a common conductor havingl a plurality of Contact faces supported thereon, a unitary base mounted over said conductor, said base having a plurality of compartments therein with one of said contact faces in each of said compartments, an individual automatic electric circuit breaker mechanism in each of said compartments and including a movable contact adapted to cooperate with said contact face to perform the 'switching operation, insulating material in back of said conductor and connected to said base to substantially enclose the main portion oftsaid conductor, and an extension on said conductor forming a terminal for connection -of circuit Wires leading current to said contact faces.

'7. Electric circuit breaker apparatus comprising a common conductor having a plurality of including a movable contact adapted to cooperate with said contact face to perform the switching operation, and a plate in back of said conductor and connected to said base. said conductor being maintained in position relative to the base by the connection between said plate and base and by interengaging parts on said conductor and base.

8. Electric circuit breaker apparatus. comprising a common conductor having a plurality of cont-act faces mounted thereon, a unitary base mounted over said conductor, said base having a plurality of compartments therein with one of said contact faces in each of said compartments, an individual automatic electric circuit breaker mechanism in each of said compartments and including a movable contact adapted to cooperate with said contact face to perform the switching `'operation, interengaging surfaces on said conductor and said base limiting relative movement therebetween except in one direction, and means preventing such relative movement in said one direction.

9. Electric circuit breaker apparatus comprising a common conductor having a plurality of contact faces mounted thereon, a unitary base mounted over said conductor, said base having a plurality of compartments therein with one of said contact faces in each of said compartments, an individual automatic electric circuit breaker mechanism in each of said compartments and including a movable contact adapted to cooperate with said contact face to perform the switching operation, and interengaging surfaces on said conductor and said base limiting relative movement therebetween except in a direction at right angles to the plane of the conductor, and a plate invback of said conductor and connected to said base and preventing such movement while the plate and base are connected.

10. Electric circuit breaker apparatus comprising a common conductor having a plurality of contact faces mounted thereon, ay unitary base mounted over said conductor, said base having a plurality of compartments therein with one of said contact faces in each of said compartments, an individual lautomatic electric circuit breaker mechanism in each of said compartments and including a movable contact adapted to cooperate with said contact face to. perform the switching operation, interengaging surfaces on said conductor and said base limiting relative movement therebetween except in a direction at right angles to the plane of the conductor, a plate in back of saidN conductor and connected to said base, and insulating portions between said plate and conductor and pressed against said conductor `by the engagement between the plate and base to maintain the conductor in place relative to the base while insulating it from said plate.

JOHN G. JACKSON. WALLACE T. AILEN. 

